The present invention relates to a roll bending or plate bending machine with a programmable working cycle, of the type whereby the bending machine comprises an upper draw roll for advancing the plate, a lower gripping roll and lateral rolls for bending the plate, said rolls being supported and connected to drive means in order to be moved towards and from the upper roll. Present invention is an evolution and a development of a previous application of the same applicant.
When bending plates to form tubes or cylindrical or frustoconical bodies and the like, with a traditional bending machine, the operator has to evaluate a number of critical parameters which each time have to be correctly calculated and controlled to obtain the finished piece with the required diameter or bend. During working the critical parameters to be evaluated concern more particularly the characteristics of the iron plate to be worked, such as thickness, its modulus of elasticity, the dimensions of the metal sheet or plate and the diameter of the finished piece. The very constructional and functional characteristics of the roll bending machine may in some cases affect the bending operations.
In present roll bending machines, an operator has initially to proceed by trial and error to establish the correct value of the plate gripping pressure and the correct position of the lateral bending rolls, intervening, if necessary, to correct or adapt the working parameters of the machine so as to obtain the piece with the required diameter. Since the characteristics of the plate may vary within broad tolerances, the operator has to intervene frequently, on the basis of his personal experience, to adapt the machine to the different characteristics of the plate to be worked, without being able to ensure repeatability and constancy of results.
There is therefore the need for a plate bending machine having a programmable working cycle, with which it is not only possible to take into account the intrinsic or inherent characteristics of the iron sheet which is to be bent at that time, but which if required is able to control its own cycle and the choice of the working parameters in relation to reference data and/or preset working parameters.
Therefore, an object of the present invention is to provide a plate bending machine which is able to perform all the working phases automatically, modifying each time the working parameters of the machine according to the characteristics of the iron sheet to be bent, thus ensuring repeatability and constancy of results.
A further object of the present invention is to provide a roll bending machine for bending plate, as mentioned previously, which is not only able to control and modifing the working cycle automatically on the basis of a set program, but at the same time is capable of evaluating in advance some of the characteristics of the new iron sheet or plate to be worked, and consequently to modify the working and functional parameters.